﻿/**
 * 2015-09-18 修改 支持amd加载方式 by fanyu  
 * 2013-7-13 修改。第一次加载时，不调用2次。 by shandl
 * 
 * This jQuery plugin displays pagination links inside the selected elements.
 *
 * @author Gabriel Birke (birke *at* d-scribe *dot* de)
 * @version 1.2
 * @param {int} maxentries Number of entries to paginate
 * @param {Object} opts Several options (see README for documentation)
 * @return {Object} jQuery Object
 */



;(function (factory) {
    if (typeof define === "function" && define.amd) {
        // AMD模式
        define([ "jquery" ], factory);
    } else {
        // 全局模式
        factory(jQuery);
    }
}(function ($) {
    jQuery.fn.pagination = function(maxentries, opts){
    	opts = jQuery.extend({
    		items_per_page:10,
    		num_display_entries:10,
    		current_page:0,
    		num_edge_entries:0,
    		link_to:"#",
    		prev_text:"Prev",
    		next_text:"Next",
    		ellipse_text:"...",
    		prev_show_always:true,
    		next_show_always:true,
    		call_callback_at_once : true,
    		callback:function(){return false;}
    	},opts||{});
    	return this.each(function() {
    		/**
    		 * Calculate the maximum number of pages
    		 */
    		function numPages() {
    			return Math.ceil(maxentries/opts.items_per_page);
    		}
    		
    		/**
    		 * Calculate start and end point of pagination links depending on 
    		 * current_page and num_display_entries.
    		 * @return {Array}
    		 */
    		function getInterval()  {
    			var ne_half = Math.ceil(opts.num_display_entries/2);
    			var np = numPages();
    			var upper_limit = np-opts.num_display_entries;
    			var start = current_page>ne_half?Math.max(Math.min(current_page-ne_half, upper_limit), 0):0;
    			var end = current_page>ne_half?Math.min(current_page+ne_half, np):Math.min(opts.num_display_entries, np);
    			return [start,end];
    		}
    		
    		/**
    		 * This is the event handling function for the pagination links. 
    		 * @param {int} page_id The new page number
    		 */
    		function pageSelected(page_id, evt){
    			current_page = page_id;
    			drawLinks();
    			var continuePropagation = opts.callback(page_id, panel);
    			if (!continuePropagation) {
    				if (evt.stopPropagation) {
    					evt.stopPropagation();
    				}
    				else {
    					evt.cancelBubble = true;
    				}
    			}
    			return continuePropagation;
    		}
    		
    		/**
    		 * This function inserts the pagination links into the container element
    		 */
    		function drawLinks() {
    			panel.empty();
    			var interval = getInterval();
    			var np = numPages();
    			// This helper function returns a handler function that calls pageSelected with the right page_id
    			var getClickHandler = function(page_id) {
    				return function(evt){ return pageSelected(page_id,evt); }
    			};
    			// Helper function for generating a single link (or a span tag if it's the current page)
    			var appendItem = function(page_id, appendopts){
    				page_id = page_id<0?0:(page_id<np?page_id:np-1); // Normalize page id to sane value
    				appendopts = jQuery.extend({text:page_id+1, classes:""}, appendopts||{});
    				if(page_id == current_page){
    					var lnk = jQuery("<span class='current'>"+(appendopts.text)+"</span>");
    				}
    				else
    				{
    					var lnk = jQuery("<a>"+(appendopts.text)+"</a>")
    						.bind("click", getClickHandler(page_id))
    						.attr('href', opts.link_to.replace(/__id__/,page_id));
    						
    						
    				}
    				if(appendopts.classes){lnk.addClass(appendopts.classes);}
    				panel.append(lnk);
    			};
    			// Generate "Previous"-Link
    			if(opts.prev_text && (current_page > 0 || opts.prev_show_always)){
    				appendItem(current_page-1,{text:opts.prev_text, classes:"prev"});
    			}
    			// Generate starting points
    			if (interval[0] > 0 && opts.num_edge_entries > 0)
    			{
    				var end = Math.min(opts.num_edge_entries, interval[0]);
    				for(var i=0; i<end; i++) {
    					appendItem(i);
    				}
    				if(opts.num_edge_entries < interval[0] && opts.ellipse_text)
    				{
    					jQuery("<span>"+opts.ellipse_text+"</span>").appendTo(panel);
    				}
    			}
    			// Generate interval links
    			for(var i=interval[0]; i<interval[1]; i++) {
    				appendItem(i);
    			}
    			// Generate ending points
    			if (interval[1] < np && opts.num_edge_entries > 0)
    			{
    				if(np-opts.num_edge_entries > interval[1]&& opts.ellipse_text)
    				{
    					jQuery("<span>"+opts.ellipse_text+"</span>").appendTo(panel);
    				}
    				var begin = Math.max(np-opts.num_edge_entries, interval[1]);
    				for(var i=begin; i<np; i++) {
    					appendItem(i);
    				}
    				
    			}
    			// Generate "Next"-Link
    			if(opts.next_text && (current_page < np-1 || opts.next_show_always)){
    				appendItem(current_page+1,{text:opts.next_text, classes:"next"});
    			}
    		}
    		
    		// Extract current_page from options
    		var current_page = opts.current_page;
    		// Create a sane value for maxentries and items_per_page
    		maxentries = (!maxentries || maxentries < 0)?1:maxentries;
    		opts.items_per_page = (!opts.items_per_page || opts.items_per_page < 0)?1:opts.items_per_page;
    		// Store DOM element for easy access from all inner functions
    		var panel = jQuery(this);
    		// Attach control functions to the DOM element 
    		this.selectPage = function(page_id){ pageSelected(page_id);};
    		this.prevPage = function(){ 
    			if (current_page > 0) {
    				pageSelected(current_page - 1);
    				return true;
    			}
    			else {
    				return false;
    			}
    		};
    		this.nextPage = function(){ 
    			if(current_page < numPages()-1) {
    				pageSelected(current_page+1);
    				return true;
    			}
    			else {
    				return false;
    			}
    		};
    		// When all initialisation is done, draw the links
    		drawLinks();
            // call callback function
    		if (opts.call_callback_at_once) { // 修改。第一次加载时，不调用2次。
    		    opts.callback(current_page, this);
    		    //opts.call_callback_at_once = false;
    		}
            
    	});
    }
}));